Catalysts
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2018
·Vol. 8
·期 2
·53
·
IF 3.465
Yuanyuan Zhao,Ya Chu,Xiuping Ju,Jinsheng Zhao,Lingqian Kong,Yan Zhang
In this work, a nitrogen-containing bidentate ligand named 5,5′-(9-octyl-9H-carbazole-2,7-diyl)bis(1,10-phenanthroline) (OCBP) was synthesized as a nitrogen precursor for making an oxygen reduction catalyst. The 1,10-phenanthroline unit provides a coordination site for copper ions, and the resulting Cu-Nxunit may be responsible for the catalytic activities of the catalyst. Carbon black was selected as a support to improve the electroconductibility of the resulting catalyst. The metallo-supramolecule (Cu-SOCBP) was dispersed on the surface of Vulcan XC-72 carbon and was used as a catalyst (designated as Cu-SOCBP/C) for the oxygen reduction reaction (ORR). The microscope structure and surface components of the catalyst were acquired via scanning electron microscopy and X-ray photoelectron spectroscopy, as well as X-ray powder diffraction. The electrochemical property and ORR mechanism of Cu-SOCBP/C were analyzed using a variety of electroanalytical methods including cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry. These results show that Cu-SOCBP/C was successfully synthesized and that ORR was achieved mainly via a four-electron transfer process to water. Thus, Cu-SOCBP/C was an effective catalyst and might have potential application as a cathodic catalyst in microbial fuel cells, which operate in an aqueous medium.Keywords:supramolecule;ORR activity;kinetics study
研究领域:
电化学
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材料科学
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DOI
高影响因子
CELLULOSE
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2019
·Vol. 26
·期 15
·8313-8323
·
IF 3.917
Wang Chao,Yang Guihua,Zhang Xueming,Shao Lupeng,Lyu Gaojin,Mao Jianzhen,Liu Shijie,Xu Feng
Levulinic acid (LA) production from corncob acid hydrolysis residues (CAHR) using FeCl 3 as Lewis acid catalyst in green solutions of salt was investigated. The reaction kinetic relationships were determined in the temperature range of 160–180 °C, with FeCl 3 concentrations of 0.12–0.36 M, and a reaction time of 0–60 min. The maximum LA concentration of 59.0 mol% (24.5 g/L) was achieved at 170 °C in a 30% NaCl solution containing 0.24 M FeCl 3 . A pseudo first-order kinetic model was proposed to describe the cellulose deconstruction to LA. The model agreed perfectly with the evolution in the concentrations of the major compounds such as glucose, 5-hydroxymethylfurfural and LA during the CAHR hydrolysis. The kinetic model developed for CAHR was in good agreement with that previously developed for other lignocellulosic systems. Based on our kinetic model and reaction system, the LA yield is increased at the lower end of the temperature range with the higher acid concentrations. The results indicated that the concentrated seawater after desalination could be a green solvent in the biorefinery.
研究领域:
化学工程
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生物技术
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可再生能源
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
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2018
·Vol. 19
·期 7
·2047
·
IF 3.687
Yao Li,Sheng Guo,Quanjin Ren,Dandan Wei,Ming Zhao,Shulan Su,Zhishu Tang,Jin-Ao Duan
Jujubae Fructus, the dried fruit ofZiziphus jujuba, has been used as Chinese medicine and food for centuries. Triterpenic acids have been found to be the major bioactive constituents inJujubae Fructusresponsible for their hepatoprotective activity in previous phytochemical and biological studies, while few pharmacokinetic studies have been conducted. To reveal the kinetics of the triterpenic acids under the pathological liver injury state, an established ultra-performance liquid chromatography coupled with a mass spectrometry method was applied for the simultaneous quantitation of seven triterpenic acids (ceanothic acid, epiceanothic acid, pomonic acid, alphitolic acid, maslinic acid, betulinic acid, and betulonic acid) in plasma samples of normal and acute liver injury rats induced by CCl4. The results showed that there were significant differences (p< 0.05) in the pharmacokinetic parameters of seven triterpenic acids between model and normal groups. The AUC0–tand AUC0–∞of epiceanothic acid (5227 ± 334 μg⋅h/L vs. 1478 ± 255 μg⋅h/L and 6127 ± 423 μg⋅h/L vs. 1482 ± 255 μg⋅h/L, respectively) and pomonic acid (4654 ± 349 μg⋅h/L vs. 1834 ± 225 μg⋅h/L and 4776 ± 322 μg⋅h/L vs. 1859 ± 230 μg⋅h/L, respectively) in model rats were significantly higher than those in normal rats, and the CLz/F of them were significantly decreased (0.28 ± 0.02 L/h/kg vs. 1.36 ± 0.18 L/h/kg and 19.96 ± 1.30 L/h/kg vs. 53.15 ± 5.60 L/h/kg, respectively). In contrast, the above parameters for alphitolic acid, betulinic acid and betulonic acid exhibited the quite different trend. This pharmacokinetic research might provide useful information for the clinical usage of triterpenic acids fromJujubae Fructus.Keywords:Ziziphus jujuba;triterpenic acids;pharmacokinetic study;acute liver injury
研究领域:
中药学
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药理学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2024
·
IF 5.3
Balaji Panchal,Yuzhuang Sun,Cunliang Zhao,Bangjun Liu,Kai Bian,Jinxi Wang,Qiaojing Zhao
Declining fossil fuel reserves and fluctuating petroleum prices have prompted global research efforts to develop clean, renewable, and sustainable alternatives to traditional fossil fuels. In this study, a reusable and eco-friendly activation catalyst was designed by combining KOH with a polymer. A series of three polymer catalysts were synthesized, and their catalytic activities were compared with those of COP-KOH, COP-K 3 PO 4 and COP-KF. It was found that the prepared COP-KOH catalyst showed the highest activity. The catalyst was characterized by FT-IR, which confirmed the presence of potassium support successfully coordinated on the COP. Additional analyses included N 2 and BET, XPS, SEM, mapping, and basicity measurement by ICP analysis. The prepared catalysts a possessed mesoporous structure, high surface area of 4.2961 m 2 /g −1 , pore volume of 2.2439 m 2 /g −1 , and high basicity. Here, the activity and stability of the potassium modified mesoporous polymer COP-KOH catalyst in green fuel synthesis from waste fried sunflower oil was evaluated. The green fuel conversion rate of 96.42 % was achieved under optimal reaction conditions, with a molar ratio of 6:1 methanol to fried sunflower oil, a catalyst concentration of 85 wt%, a reaction temperature of 61 °C, and a reaction time of 4.5 h. A satisfactory yield of 92.1 % was obtained after use for four consecutive cycles without significant deactivation, and after the fourth cycle catalyst was reactivated with KOH. The characteristic differences in the FT-IR results of the fresh catalyst, used catalyst, and re-activated COP-KOH catalyst, indicated the mode of interaction between the catalyst and reactants. The kinetics of the transesterification reaction was also determined, and the activation energy was found to range from 20.9 to 23.4 kJ . mol −1 . The properties of the green fuel were found to be in good agreement with the ASTM D6571-02 standard. The catalyst is recyclable, and using inexpensive feedstock makes the overall process more cost-effective and environmentally friendly.
研究领域:
化学工程
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环境科学
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能源科学
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产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
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2024
·
IF 1.4
Bo Wang,Pei-ya Li,Shu-han Lu,Bin Wang,Fusheng Yang,Tao Fang
Liquid organic hydrogen carrier (LOHC) technology has unique advantages in hydrogen storage and transportation. However, the lack of research on the continuous dehydrogenation process of LOHCs has hindered the design and application of industrial dehydrogenation processes. In this work, a highly active dehydrogenation catalyst 1.5 wt% Pd/activated carbon (Pd/C) and a commercial catalyst 5 wt% Pd/Al 2 O 3 were used for the continuous dehydrogenation of dodecahydro-N-ethylcarbazole (12H-NEC). Based on a tubular reactor and lab-scale apparatus, 1.5 wt% Pd/C catalyst achieved a maximum dehydrogenation conversion of 98.3% and a maximum NEC selectivity of 95.3%, while dehydrogenation conversion and NEC selectivity with 5 wt% Pd/Al 2 O 3 were 98.3% and 97.6%, respectively. It showed the equally excellent performance between Pd/C and Pd/Al 2 O 3 , and the former has less Pd loading than the latter, with the potential of reducing the production cost of the dehydrogenation catalyst. The dehydrogenation results also indicated the difference in catalytic performance between the two kinds of catalysts. The obtained kinetics data were analyzed, and the dynamics of continuous dehydrogenation were studied to provide fundamental information for dehydrogenation scale-up.
研究领域:
化学工程
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能源科学
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产品关联
DOI
高影响因子
PLoS One
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2014
·Vol. 9
·期 4
·e95242
·
IF 3.534
Hui-Xi Zou,Nan Li,Li-Hua Wang,Ping Yu,Xiu-Feng Yan
A fundamental investigation of the biosorption of Cd 2+ from aqueous solution by the edible seaweed Sargassum fusiforme was performed under batch conditions. The influences of experimental parameters, such as the initial pH, sorption time, temperature, and initial Cd 2+ concentration, on Cd 2+ uptake by S. fusiforme were evaluated. The results indicated that the biosorption of Cd 2+ depended on the initial Cd 2+ concentration, as well as the pH. The uptake of Cd 2+ could be described by the Langmuir isotherm model, and both the Langmuir biosorption equilibrium constant and the maximum biosorption capacity of the monolayer decreased with increasing temperature, thereby confirming the exothermic character of the sorption process. The biosorption kinetics follows the pseudo-second-order kinetic model, and intraparticle diffusion is the sole rate-limiting step for the entire biosorption period. These fundamental equilibrium and kinetic results can support further studies to the removal of cadmium from S. fusiforme harvested from cadmium-polluted waters.
研究领域:
环境科学
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海洋生物学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2016
·
IF 5.31
Hefei Wang,Yongsheng Zhao,Tianyi Li,Zhen Chen,Yinan Wang,Chuanyu Qin
Calcium peroxide (CaO 2 ), as one of the solid peroxides, has been increasingly used in contaminated site remediation due to its ability to release oxygen (O 2 ) and hydrogen peroxide (H 2 O 2 ). Biodegradation can be enhanced by the existence of O 2 . Hydrogen peroxide can be used to for in situ chemical oxidation via the modified Fenton . Previous studies show inconsistent results about O 2 and H 2 O 2 release during CaO 2 decomposition. Additionally, the release characteristics of O 2 and H 2 O 2 are not evaluated in detail. A series of batch experiments was conducted to investigate the properties of CaO 2 decomposition and the release kinetics of O 2 and H 2 O 2 . O 2 and H 2 O 2 were released directly from CaO 2 dissolution and H 2 O 2 was not an essential intermediate in the conversion of CaO 2 to O 2 . The two release paths formed a parallel reaction system, with a competitive relationship between the two paths. The release of H 2 O 2 and O 2 followed a pseudo-zero-order kinetics pattern and a pseudo-first-order kinetics pattern, respectively. Increasing temperature and decreasing pH could accelerate both O 2 and H 2 O 2 release rate. However, increasing temperature could decrease the H 2 O 2 yield and increase the O 2 yield, which were similar to the impact of increasing pH.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
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2021
·
IF 4.598
Qiaohong Peng,Li Wei,Xiaoyan Zhang,Ying Wu,Khalid Mahmood,Zhengping Liu,Lisha Zhang
Ionic liquids (ILs), instead of the classical organic solvents, have shown great improvements in chemical processes. Herein, Water-insoluble alkyl- and benzyl-substituted imidazolium bis(trifluoromethanesulfonyl)imides as non-volatile and thermostable solvents were employed in the direct polycondensation of l -lactic acid (LLA). The effects of monomer concentration, reaction temperature and miscibility between the ILs and poly( l -lactic acid) (PLLA) were comprehensively investigated. Biodegradable PLLA with weight-average molecular weight as high as 132 kDa was synthesized. Compared to melt-polycondensation of LLA, far higher molecular weight could be achieved via the solution polycondensation of LLA in ILs since the viscosity of the polymer melt could be significantly reduced based on the dilution effect of ILs. Polycondensation kinetics of LLA in bulk and in an IL demonstrated that the IL could accelerate the polycondensation of LLA. Influence of lactide, the main by-product, on the polycondensations of LLA was also studied kinetically.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Chinese Journal of Aeronautics
·
2025
·
IF 5.7
Jun LIU,Tianyu YANG,Yi XIAO,Qilong YAN,Yunlan SUN
To gain insight into the fine interfacial control mechanism exhibited by oxidant-coated Al powder to improve combustion performance, we prepared Al/AP and Al@AP composite fuels using ball milling and spray-drying technology. The thermal reaction characteristics, AP decomposition behavior, and decomposition reaction pathways of Al/AP and Al@AP composite fuels were investigated using thermal analysis and Ab Initio Molecular Dynamics (AIMD) calculations. Under the influence of fine interfacial control, the low-temperature decomposition heat release peak of AP was delayed by 25.5 °C, while the high-temperature decomposition peak was advanced by 36.2 °C, leading to an increase in the decomposition heat release of AP from 410.7 J/g to 1 068.7 J/g. Compared to the unclad structure, the apparent activation energy of AP in low-temperature decomposition increased, and slightly decreased during high-temperature decomposition in the Al@AP composite fuel. The physical model of AP decomposition shifted to the model with higher degrees of freedom and a faster diffusion rate, characterized by rapid bidirectional diffusion at the interface. Furthermore, due to fine interfacial control, the oxidation reaction pathway of Al has been altered, changing from the final products of AP decomposition (O 2 , Cl 2 , etc.) to the direct oxidation of AP decomposition intermediates (HClO, ClO 2 , etc.). This accelerated and strengthened the oxidation reaction process of Al. As a result of these performance improvements, the final combustion temperature of Al@AP in the Microcanonical Ensemble (NVE) system stabilized at 2 370 K, which is significantly higher than 1 400 K observed for Al/AP, indicating enhanced ignition and combustion performance.
研究领域:
材料科学
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化学工程
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燃烧技术
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Xiangxue Zhang,Nina Fei,Qianhong Wang,Ali Raza Khan,Wenyao Chen,Gang Qian,Jing Zhang,De Chen,Xuezhi Duan,Xing-Gui Zhou,Weikang Yuan
Oxygen vacancy regulation in metal catalysts has emerged as a crucial strategy for efficiently degrading volatile organic compounds (VOCs), while the acquisition of kinetics and mechanistic insights into the oxygen vacancy roles remains highly desirable yet challenging. Herein, we conduct a combined kinetics and mechanistic investigation into the oxygen vacancy effects of Cu catalysts on toluene oxidation. Cu catalysts with varying oxygen vacancy contents are prepared using three representative metal oxide supports, including reducible ZrO2 with strong oxygen storage capacity, reducible ZnO, and unreducible Al2O3. The toluene oxidation as well as CO oxidation are tested for these catalysts, revealing the superior catalytic activity of Cu/ZrO2 catalyst. Multiple charactrizations demonstrate that the strong reducibility and abundance of oxygen vacancies within the Cu/ZrO2 catalyst are the key factors for these reactions. A redox-based kinetics strategy is further applied to decouple the reduction and oxidation steps, thus affording a rate diagram to elucidate the promotional effects of oxygen vacancies on toluene decomposition. Additionally, in-situ DRIFTS study unveils the reaction pathway, showing the transformation from toluene to benzyl alcohol, benzaldehyde, benzoate, phenol, anhydride, carbonate, and ultimately to CO2. As a result, the oxygen vacancy-tuned rate-relevant step is disclosed, shifting from C-H bond cleavage for the Cu/Al2O3 catalyst with limited oxygen vacancies to the C=O and C=C bond cleavage for the Cu/ZnO and Cu/ZrO2 catalysts with more oxygen vacancies. The kinetics and mechanistic insights gained here would help guide the design of highly efficient oxidative catalysts by tuning the oxygen vacancies of support.
研究领域:
催化化学
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环境科学
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材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Qilin Xu,Jun Chen,Zihao Wang,Yongjun Zang,Guosi Li,Fucheng Zhu,Dong Liu,Chaoyue Sun
Olaparib is a top-selling pharmaceutical approved for the treatment of ovarian cancer. Herein, a two-step cascaded flow process was developed to synthesize Olaparib in microreactor. Since two different acyl groups are in the piperazine ring of Olaparib, a highly selective monoacylation route of piperazine is crucial for the efficient synthesis of Olaparib. For the first step (i.e., the monoacylation of piperazine), N , N' -carbonyldiimidazole was screened as coupling reagent due to its excellent selectivity , safety and greenness, a high monoacylation yield of 83 % was obtained in the microreactor. To understand the selective monoacylation reaction more deeply, the intrinsic kinetics was investigated based on mechanism cognition and experimental data. The established kinetic model was in good agreement with the experimental results in validation experiments. To further realize continuous manufacturing, the following step (i.e., amidation) was cascaded with the monoacylation in a microreactor system, Olaparib was continuously synthesized in the two-step cascaded microreactor with an overall yield of 78 % within 25 min. Relative to existing processes, the reaction steps were reduced, the economy and efficiency were remarkably improved, indicating efficient process intensification.
研究领域:
药物化学
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合成化学
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生物医学工程
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产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2021
·
IF 7.963
Xiaoling Ma,Wenlong Wang,Chenggong Sun,Hui Li,Jing Sun,Xin Liu
In light of the promising merits of large surface area, uniform pore size, and tunable functional groups, metal-organic frameworks (MOFs) have great potential to be utilized for adsorbing volatile organic compounds (VOCs). In this study, three Fe-based MOFs, MIL-100(Fe), MIL-101(Fe), and MIL-53(Fe), were synthesized systematically and used to adsorb a typical VOC, toluene. Static adsorption, dynamic breakthrough curves , and adsorption kinetics were conducted to assess the adsorption performance. Additionally, the surface functional groups, pore structure, and morphology were systematically characterized by means of XRD , SEM, XPS, FTIR and N 2 adsorption-desorption analyses to reveal the cause of the difference in adsorption of these Fe-based MOFs. The results revealed that the maximum equilibrium adsorption capacity of 663 mg/g was achieved by MIL-100(Fe) with the highest specific surface area and pore volume. The dynamic adsorption of toluene on MIL-100(Fe) was in accordance with the pseudo-first order kinetic model and the Langmuir isothermal model. The formed π-π stacking interaction between organic ligands and the benzene ring in the MIL-100(Fe) cluster is the primary adsorption mechanism based on XPS analysis. Moreover, MIL-100(Fe) was easily regenerated via microwave irradiation with a negligible adsorption capacity decrease after three cycles. This work highlights the feasibility of hierarchical porous Fe-based MOFs as toluene adsorbents and promotes the application of MOFs in the field of pollution control .
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）